Method and system for radio frequency location based on token ring under Internet of things environment

Abstract

The invention discloses a method and system for radio frequency location based on a token ring under an Internet of things environment. The method comprises the steps that a road sign network is composed of road sign nodes in a locating zone; after a token is generated by ASN, the token is broadcasted to the road sign network through a downlink channel; after the token is obtained by the road sign nodes in the road sign network, radio frequency signals are sent to locating nodes entering the locating zone through the downlink channel and the token is sent out; the radio frequency signals sent by the road sign nodes are received by the locating nodes, an RSSI value of each road sign node is obtained and sent to an ASN through an uplink channel, and each RSSI value is sent to a wireless locating server through the Internet by the ASN; the positions of the locating nodes are calculated through the wireless locating server according to the received RSSI values. The token is maintained by the ASN and transmitted among the road sign nodes, locating frames can be sent only after the token is obtained by the road sign nodes, and conflict is effectively avoided when data are sent among the road sign nodes.

Description

technical field [0001] The invention relates to the positioning of nodes in a wireless sensor network, in particular to a token ring-based radio frequency positioning method and system in an Internet of Things environment. Background technique [0002] Wireless sensor networks are event-oriented monitoring networks. For most applications, the data sensed without knowing the location of the sensor is meaningless. It is one of the most basic functions of the sensor network to determine the location of the event or the location of the node that obtains the message in real time, and it is also the premise of providing the location information of the monitoring event, so the positioning technology plays a key role in the effectiveness of the sensor network application. [0003] In wireless sensor networks, according to whether the actual distance or angle between nodes is measured during the positioning process, it can be divided into ranging-based positioning algorithms and non-...

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Problems solved by technology

[0004] The above existing node positioning methods all have their own shortcomings, such as TOA requires precise clock synchronization, TDOA requires nodes to be equipped with ultrasonic transceiver devices, and AOA requires antenna arrays or microphone arrays. These three algorithms have high requirements for hardware; RSSI technology It mainly uses RF signals, and the nodes themselves have wireless communication capabilities, so it is a low-power, cheap ranging technology. However, the MAC protocol of the existing RSSI positioning method uses mobile nodes to send information and fix road signs. The working mode of the node receiving information, when there are multiple mobile nodes in the same area, the mobile nodes will conflict with each other when sending information, the capacity of each area of ​​the positioning system is limited

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